Most, if not all of my readers will be accustomed to having clean running water readily available to them. Kitchen, laundry, bathroom, garden – the supply of water in developed countries (especially urban and suburban areas) is almost universal.

But it wasn’t always like that.

This loose series of blog posts has, admittedly, a bit of a focus on fantasy world-building, as that’s my preference. And a lot of fantasy fiction has the European middle ages as its basis. And during that time and for quite a long time afterward, clean drinking water was not a sure thing. Whilst it made sense for a single town to pull water out of the river on the upriver side and put their sewage in the downstream side, what about the next town down the river? And the next?

When the colony of Sydney was founded, we had this kind of problem. There was a nice clean stream flowing down into the harbour that was quickly overrused. People were trying to pull water out of it right next to where others were putting waste into it. Within a few decades, the first of a series of increasingly large engineering efforts to secure clean water for the burgeoning colony were begun. The Tank Stream now runs in a tunnel underneath the heart of the CBD and most of Sydney’s clean water comes from an large dam some fifty miles or more to the west.

But this isn’t a feat of industrialised society. The Romans were widely lauded for their aqueducts capable of transporting clean water many miles to their cities. Rome alone had more than half-a-dozen aqueducts delivering water to the city. Importantly, the Romans had programs for maintenance and repair and prided themselves on their public baths. Yes, public baths. Household plumbing was likely beyond the Roman’s ability, and possibly beyond what they could imagine. But their whole society viewed personal cleanliness and privacy quite differently to our current western secular society.

Of course, in an invented world, you can create as much or as little of this as you wish. Quite how your fantasy world gets its water to those who need it isn’t necessary to describe or even design in detail. However, you probably should be aware of it. A city of two millions souls with huge public fountains and baths would work situated in a fertile landscape within a hundred miles of snow-capped mountains. The same city would ring false situated on a desert coast with no river in sight. Unless you had designed some magical source of water (it has happened).

Likewise, how water is made available to your world’s characters can drive the story. Public baths can be could for cladestine meetings and illicit hookups in ways that could be quite different in today’s world. The frequency of bathing could be a plot point. Amongst other things, it has an effect on how often they change their clothes. Or wash them.

Or cook. The cottages of Lancre in Terry Pratchett’s Discworld, if they have an indoor pump will have it in the scullery. This contributes directly to the house design: the washing is done in one room, but the cooking is done in another. This is world-building in the small.

Where your water comes from has a subtle and powerful influence on how a world works. And I’ve barely touched the subject.